The good people at Cookware.com wrote the following article for you (my comments follow in Italics).
Cookware for a Gluten-Free Lifestyle
Anyone that has been diagnosed with a food related allergy understands that the smallest trace of that particular ingredient can result in a number of painful or uncomfortable circumstances. For this reason, it’s vital to take extra care with the cookware sets we use on a daily basis as many sets that have come in contact with our known allergens can set off a reaction right away. While many people with gluten-free diets opt to invest in their own cookware collection in an effort to eliminate any chance in coming in contact with wheat, others turn to cast iron cooking due to the cooking properties of this particular material.
Cast iron cookware is well known for its durability and nonstick surface that is far superior to sets made from other materials such as stainless steel or aluminum. Well seasoned cast iron surfaces that have been coated correctly in a heated oven will fill the cracks of each pot and pan, leaving you with a cookware set that should repel water. After this process has been completed, you’ll be able to cook a number of different meals without having to worry about the mixing of flavors that aren’t appropriate for a particular dish. In addition to pots and pans, the first things you want to replace in a non gluten-free household are your cutting boards and colanders as these are items that have come in contact with wheat products the most.
When it comes to baking, there’s no need to invest in separate trays and containers unless you are in need of a new set. Baking disposable liners can be used in muffin trays, baking sheets, and glass pans for when you want to make delicious gluten-free desserts or breakfast items. It’s important to label or color code cookware, bakeware, and food storage containers in a mixed diet household in order for people with a gluten intolerance to avoid contact with even the smallest traces of wheat.
When going gluten-free, you don’t need to buy new cast iron cookware. You cannot, however, use the cookware for both gluten and gluten-free cooking, as the food particles can stick to the seasoning or in the cracks. To prepare used cast iron cookware for gluten-free use, place it in an oven and run the self-cleaning cycle. It gets so hot that all food particles will turn to ash, and you can brush them off (obviously after the cookware has cooled). Then re-season your cookware as if it were brand new. I do not recommend this in the summer in hot climates like Texas. It will take forever to cool the house.
Another option is to sand-blast the cookware. You laugh, but I actually had a friend do this. He found some men working with a sand blaster near his house, and asked them to do this. I think, however, it might require a gentle hand.
What is your favorite type of cookware? I have yet to find mine.